Pathogen-mediated selection for MHC variability in wild zebrafish

Hypothesis: Genes of the major histocompatibility complex (MHC) show high variability, which is believed to arise through pathogen-mediated selection. Organism: Zebrafish (Danio rerio) from seven independent natural populations. Location: Bangladesh: two sites in Khulna District in the River Ganges drainage, and five sites in Mymensingh District in the River Brahmaputra drainage. Methods: We investigated the relationship of parasite abundance and diversity with allelic variability of the MHC class II B gene in natural populations of zebrafish. A sample of 120 zebrafish was screened for metazoan parasites, and a subsample of 77 was assessed for immunogenetic variation. In total, 2475 metazoan parasites from 23 taxa were identified and 13 unique MHC class IIB alleles were isolated. Conclusion: We found no evidence…